The most common and most likely answer to this crossword clue is the 6 plus 5 letter word POLICE STATE
I've seen this crossword clue in The Times
P
O
L
I
C
E
S
T
A
T
E
More clues leading to the result POLICE STATE
- Cut back — result of freeze, say — in authoritarian regime
- Guards art gallery where the Constables have great power?
- Caste tortured in elegant and repressive regime
- A sect terribly restricted by civil regime denying basic rights
- It lost peace producing tyranny
- Breaking with courtesy, in France it’s a harsh regime
Buddy explains!

The straight part
We know that "authoritarian regime" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case authoritarian regime = police state.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.